Fig. 12

Upper panel: Flow cytometry studies to enumerate very small embryonic-like stem cells (VSELs) in chemoablated testis with and without FSH treatment (10 IU). VSELs were studied as small-sized (2–6 μm), LIN−/CD45−/SCA-1+ cells. VSELs survived in chemoablated testes (0.045 + 0.008% of total cells) and further increased after FSH treatment (0.1 + 0.03%) [51]. Lower panel: Immuno-phenotyping studies for OCT-4, PCNA and FSHR positive cells in chemoablated testes with and without rFSH (10 IU) treatment. FSH resulted in increased numbers of OCT-4 (from 1.34 to 2.61%), PCNA (from 1.43 to 6.8%) and FSHR (from 1.8 to 4.5%) positive stem cells. FSH exerts a direct stimulatory effect on testicular OCT-4 positive stem cells since they express FSHR [52]